Create a timber tunnel portal over a single N scale track. Color with Earth Colors Liquid Pigment. Tunnel Portals, Retaining Walls, Culverts, and Roads reinforce natural terrain contours and add functionality, realism and interest to your layout.. Features These timber tunnel portals are cast in high-density Hydrocal; Wide enough for one N scale track to run through; These white casts are authentically detailed in appearance and texture; You can use these portals alone or in combination with retaining walls; Create ultimate scenic realism simply and economically; Ready for staining or painting right from the box; Easy to follow instructions for installation of portals; .